Tjernlund Radon Vac  - RMS160

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The Radon Vac is a fan manufactured by Tjernlund.  The fan is designed to be installed inside the house or basement and utilized as a sub-slab depressurization fan.  The exhaust from the fan is discharged directly to the outside.  Note that according to the ASTM E2121 and the AARST Radon Mitigation Standards radon fans cannot be installed under or inside a living space and the discharge must be routed above the roofline.  This fan installation would not be allowed in any regulated US state that abides by these standards. Canada and Alaska do however allow radon sub-slab depressurization systems to have the fan installed inside with the exhaust at grade because of the concern that their cold climate would cause moisture in the vented soil gas to condense and freeze inside piping and fans that are installed outside.

Here is a picture of the RMS160

The fan is installed inside and the exhaust is vented directly to the outside

The exhaust hood that comes with the fan has side openings that dilute the exhaust and adjustable dampers to modify the speed of the exhausting airflow in order to direct the radon exhaust away from the building.

In order to properly adjust the dampers a plastic bag is provided with the fan,  The bag is taped around the exhaust orifice after the radon mitigation system has been installed and all sealing has been completed.  The fan is turned on and the time it takes to fill the garbage bag is then compared to a chart provided by the manufacturer that specifies how the exhaust dampers are to be adjusted.  The picture below is the bag method being tested by WPB.

During the WPB test the resistance to the fan was adjusted and each time the airflow was measured using this method.  The dampers were then adjusted and the exhaust airflow velocity was measured with a pitot tube.

This is the exhaust velocity measurement.

The following chart is the results of the airflow testing using the method described.

Here is the performance of the Radon Vac RMS160 Fan

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